Donald Trump, the presumptive Republican nominee in November’s election, has joined an unusual club: presidential contenders who have also been convicted of a crime.

Before Trump was found guilty on 34 felony counts of falsifying business records in a historic verdict on Thursday, the most well-known convict seeking the Oval Office had been Eugene Debs, a socialist who conducted his presidential campaign behind bars in 1920. 

A fiery labor activist, Debs had established himself as an acclaimed orator before he was imprisoned for publicly expressing anti-war sentiment. While Republican Warren Harding won that year’s election by a landslide, defeating Democrat James Cox, Debs managed to secure nearly 1 million votes from his Atlanta prison cell —  which Allison Duerk, director of the Eugene V. Debs Museum in Terre Haute, Indiana, called “remarkable.”

“He couldn’t even use his most powerful tool, which was his voice,” she said, adding that he was permitted to put out a short weekly press release during the campaign season but otherwise relied on others in the Socialist Party to get the word out for him. His supporters wore pins with his photograph and inmate number on them, which read: “Convict No. 9653 for President.” 

Historians say there are key differences between Debs and Trump. For starters, Debs was serving what he anticipated would be a 10-year sentence when he ran for president, and Trump may avoid prison time entirely: When he’s sentenced on July 11, he faces penalties that range from a fine to up to four years in prison.

The crimes the two men were accused of, and their responses to the allegations, also differ significantly. Trump pleaded not guilty to his charges, which were related to a hush money payment that his former lawyer made to adult film star Stormy Daniels as the 2016 presidential election approached.

Debs, on the other hand, admitted what he had done — and took pride in it.

A founding member of the Socialist Party who had already run for president on the party’s ticket four times starting in 1900, Debs’ turning point was a June 1918 speech he gave at a rally in Canton, Ohio. The country was still embroiled in World War I, and Debs knew that criticizing U.S. wartime policy or then-President Woodrow Wilson would run afoul of the Sedition Act of 1918, an amendment of the 1917 Espionage Act that curtailed free speech rights. 

So he delivered a delicately worded, but searing, address in protest of the war, arguing that American men were “fit for something better” than “cannon fodder.” His wording was not careful enough: Debs was later arrested and tried as a traitor.

Debs appealed the case, which went to the U.S. Supreme Court. He never expressed remorse for his anti-war, pro-free speech stance. At his sentencing, he informed the judge that he would not have retracted any of his address. “I ask no mercy, I plead for no immunity,” he said.

After a couple of months imprisoned in West Virginia, Debs was transferred to a federal prison in Atlanta to serve the rest of his sentence. He ended up being commuted by then-President Harding, leaving the facility in December 1921 as inmates cheered him on.

“He was loved by, and loved, his fellow inmates,” said Lisa Phillips, a labor historian and professor of history at Indiana State University. “He believed people were imprisoned because of extraneous circumstances that weren’t in their control — poverty or whatever the case was. In his case, it was for speaking his mind.” 

There have been lesser-known individuals who tried a shot at the presidency from behind bars: Church of Latter-day Saints founder Joseph Smith ran while awaiting trial for treason in 1844, and Lyndon LaRouche ran a 1992 campaign from a prison cell following a 1988 conviction for conspiracy and mail fraud, among other charges.

Life after prison was not easy for Debs. He died in a sanitarium at the age of 70 in 1926, much more worn down physically and mentally than he had been before going to prison.

But the efforts he was so passionate about have lived on, said Duerk, the Debs museum director.

“There’s not a person alive, at least in the U.S. who works for a living, who doesn’t directly benefit from the movements that Debs was a part of,” she said. “He was campaigning for president and organizing workers around the eight-hour day, around child labor laws, around workers’ compensation, minimum wage safety protections. He was campaigning on what would become social security.”

“He was able to unite different struggles,” Duerk added. “The legacy is so big.”